1. Field of the Invention
This invention relates to a portable household-type electrically heated steam iron for smoothing and pressing cloth goods or the like; and more particularly, to an electric steam iron having an aluminum upper heating and steam generating body member and a ceramic lower sole plate member.
2. Description of the Related Art
In general, an electric steam iron comprises a housing with a handle for holding the iron, a steam generating chamber, electrical heating elements for heating the iron and generating steam, electrical current control devices and supply cord device, and a sole plate having a flat boat-shape bottom surface with steam outlet passages for engaging the material to be ironed.
Most portable electric irons are heated by one or more electric resistance heaters including one or more wire-like resistors which can be connected in circuit with a source of electrical energy. The resistance heater elements can be installed in or above the sole plate portion of the iron.
In the past, conventional commercially-available sole plates have been made of metallic material, such as aluminum or steel. An advantage of aluminum is good heat conductivity and a relative low specific weight. However, the ability of an aluminum sole plate to resist scratching, scoring and similar damage is unsatisfactory. A sole plate which is made of steel is more resistant to wear; however, it is heavier and its thermal conductivity is less satisfactory than aluminum.
It has been suggested that a sole plate may be made from a main aluminum body portion or core which is electrically heatable and carries a thin-walled base plate of steel to contact the article to be ironed. If the iron is a steam iron, the sole plate must have openings for discharge of steam and the relatively thin base plate may undergo permanent deformation in the region of such openings which affects the quality of the ironing operation.
U.S. Pat. No. 4,835,363 discloses and electric steam iron heated by a halogen lamp and having a ceramic sole plate made from a ceramic material which transmits infrared light. U.S. Pat. Nos. 1,010,093; 2,179,890; 2,241,067 and U.S. Pat. No. 3,906,187 disclose electric irons having a glass sole plate.
U.S. Pat. Nos. 4,613,135, (vaporizer) 4,511,339, (steam cover and passage), U.S. Pat. No. 3,492,063 (nozzle) disclose steam iron apparatus including parts made of ceramic material. Ceramic material has also been used in other ironing apparatus such as an ironing board cloth underlay with a ceramic heating element (U.S. Pat. No. 4,452,931). U.S. Pat. No. 2,222,327 discloses an electric iron with a top housing 6 made of plastic material, a cast aluminum bottom presser plate 9 with a copper plate and a thin plate of isinglass therebetween. U.S. Pat. No. 3,098,922 discloses an electric infrared lamp heated iron having an aluminum sole plate 4. Cooking stove elements have been made of ceramic material as illustrated by U.S. Pat. Nos. 4,296,311 and 4,178,500.